/* 预处理 */
html, body, ul {
    margin: 0;
    padding: 0;
}
* {
    /* box-sizing: border-box; */
    list-style: none;
    text-decoration: none;
    font-size: 14px;
}
.fl {
    float: left;
}
.fr {
    float: right;
}
.clearfloat:after {
    display:block;
    clear:both;
    content:"";
    visibility:hidden;
    height:0;
}
.clearfloat {
    zoom:1;
}